Autographic recording torque testing machine



May 18', 1948.

F'IE. I

D. M. WARNER AUTOGRAPHIC RECORDING TORQUE TESTING MACHINE v Filed March1l, 1944 4 Sheets-Sheet l Amb i-IEA- INVENTOR A TTORNE YJ' May 18, 1948.D. M. WARNER AUTOGRAPHIC RECORDING TORQUE TESTING MACHINE Filed March11, 1944 4 Sheets-Sheet 2 I N VEN TOR 7M MRA/AE1? ATTORNEYS May 18,1948. D. M. WARNER AUTOGRAPHIC RECORDING TORQUE TESTING MACHINE 4Sheets-Sheet 5 Filed March l1, 1944 F'IE. B

FIE, 1l

INVENTOR ATTORNE YJ May 18, 1948. D. M. WARNER AUTOGRAPHIC RECORDINGTORQUE TESTING MACHINE Filed March 11, 1944 4 Sheets-Sheet 4nntlnnbrlunununnuunnununh unnnaonnnuuunnnnnunnnncq INVENTOR.

Patented May 1s, 194s Aurroemenlonncoiiinfronoun A...TESTING MAcniNEtime? mais.: @iride Warneriexecutrix of said David M. Warner,

deceased factured Iand"-usedby-or foi-the yGovernment forgovemm'entalnurposeeewifbhout the payment t me. of'enyf-royaityhereoneThis invention rela-,teseto` torque -rtestinge-maschines--forethe'applieation--toffand measurement oftwist,ing or rotational momenti@Vmaterials, parts; or-` assemblies; and "partieuiarlywto af-machinev Vforlmeasuringthe torguefrequiredwo-roand coming oi. Such -a'friutIcontainingHa-Pfrietigri. or locking device wlthinpitselfg, intended toopposeor prevent free rotation on the bolt, is caneda selig-lookingmiti? c -f .A favored, form of self-lockinglnut presently used bin.large' volume is. fone; which ldepends-cr its locking ability nentirelyjqniranincorporated feature or device whichl .applies lth e-necessaryamount 'of brakingVv friction` tothee-bolt threads independent of any,friction resulting-ironie as- Sembly..1oa.d ',to develop the-desiredfamountfof torsional resistance' teU turning --`thebelt. However, if theself-contained -braiging -friction o thesenuts istoo great there isdangeizvofg damaging, the ithreads .0.1i- .the baltsend *activer-Seli.

if-the frietionel' resistance to turningis insuli cientl'tlie nut mayloosen and come oil, due to vibration. il'. Lg.. Tr J: j

f ,Where this, type fastening @is employed, it` is therefore; highlyessential.: that the-rtightnesssbetween bolt and nut"be1l;eptpnot onlyata--high yalueybut to aunitormes-tinrn'lard,n as between all boltsandnutsioi` aigiven size; Itis therefore an object pf^ this .inventioxrfteprovide/a machine whichV may beset forefgiven vsiziedebolt:and nut,andgwhich-iwill thereaftermeasure` and "graphically record Vthevtorque'tenente turn the threads of aseries efe-bolts.'either-into'iortoutQorithose of. the correspondin'gmuts and-ithedegreeofuniformityuingthe irictional :resistance at theidifferentnpartsietthefsame bolt or between diierent bolt-softhesameesizeoewf e.- ...i f@ther :obj eets will-ebe-recognized asethe invention i isfurthervidescribed Yand-z reference made i 3to the .drawingss ,Theiautographicerecordinaztorque locking-'nutsandtm making of continuous.coinplete agraphic ...records of the. .torque developed throughoutthe-,duration-.ofthefgtest.'in-both installation and.` removal .operationslthrough, A any number .of-.cycles at room or at higher or lowertemperatureswi It consists essentially-.of=.units as follows :1,

Driving :unit .tm screw Ydine-bolt .intov .and outa'ofithe-nuh which maybe called the torque applying unit-.w :f .Y fg-1 :1 f. B...Torque.weighing uni-t .to hold either. the nut cin-bolt Aand to.weig'hfvtheitorque developed bythe nut `during the complete series ofturning operations. i., .-v

Autographicreeording unit to make,l acornp'lete graphic `record ofthetorque developed by the-nut .i;lirougl'i'out.thel tester-this part of-"the apparatus may be called the torque recording wvand, 'zij w.:l.x'..;.; d .2.. ,r-.Dsf'lail.stools` for.anchoring the outer end` ofthe. torquey resistance.` .ban and ...adjustable `to the requireddistance ffrom thenweighing unit, lof which it; is. amartgzthis partbeing termed the tor-queresistingjunit.A 1

. f e eBase or xsupporting.fframe. .u-ponswhichvthe unitsof: .thetorquetesting machine are mounted foroperation` Inv-the drawinga f1 Figa-.1 isa top plan view of the complete machine. c i. t f

Fig. 2 is a front elevationrf. .Fia B\is-..a;transverse sectionztaenfon.the line .rz-e3 @eilig-f Zivsliowineihe lead-screw 4operatinggearftrain :off theetoreueepplyingi unitz Y. 'f -i v Fig. 4 is atransverse sectiontaken ontheline 4wd cieli-ig;A 2^,.showingthegeartrain and other feedfinechanism for operating the torque re- @Ording t.Y

.isa transverse. Section .taken ,onine line `5.-,15. of Fig. v2,4sneezing` the torque resisting unit looking toward the left.

Fig, 6 shows an elevational view noi apart of v the feed mechanismeshown in Fig. 4 and viewed from thejnegf-B of'-Fig.-4,'f Fig-"7 isfaright-hand Aend viewed-Fig. l6 with aportion broken away to show theinterior construction. 'f .e 1 f- 8 is-a leftehandf-end viewof Fig..6,with a portion broken away to show the interior construc-tion. Figs.Brand lodare front, and endfviewsa-.respectively, of the rotor shown inthe assembly of Figi-16.

Fig. 11 is e in conducting a test.

a graph mad Fig. 12 is a transverse section taken at I2|2 of Fig. 1showing the indicator wheel and rod.

Figs. 3 to 10 are drawn to a larger scale than Figs. 1 and 2.

Like reference characters refer to like parts throughout the severalviews.

Referring now to the drawing, a bed plate |0, which is somewhat in theform of a lathe bed, carries, at the right end, a traveling head |2; onthe middle portion, a torque measuring head I4; and at the left end, atail stock I6. A recording mechanism |8 is attached to thetorquemeasuring head I4 and is operated therethrough. The several units l2 to8, inclusive, each perform a separate function in the testing vof thethreads. The head I2 is arranged to hold the bolt and rotate it backwardand forward and simultaneously move it axially back and forth at therate which it would move if it were being screwed into and out of astationary nut. 'Ihe torque measuring head I4 has provision for holdingthe nut against the torque occasioned by driving the bolt into it and ayielding means for measuring the degree of torque thus required.

The recording mechanism |8 translates the torques required to turn theboltA into and out of the nut into transverse oscillations, and recordsthem on a moving paper roll. Provision is made whereby the paper rollmoves at the same rate and in the desired direction, whether the boltsare rotated one way to turn them into the nuts, or the other way to turnthem out of the nuts. The tail stock I6 is provided for holding a torquerod, which holds the spindle of the torque measuring head |4 againstrotation when the threads are being tested.

The traveling head I2 comprises a base 20 with two uprights 22 and 24,which support the bearings 26 for the hollow shaft 28. A solid spindle30 is axially slidable in the hollow shaft 28, but is provided withspline means to prevent relative rotation between the shaft and spindle.By employing this construction, the spindle 30 may be pushed back intothe hollow shaft 28 to facilitate entry or removal of the work to betested. A crank 32 is attached to the hollow shaft 28 by a pin 34,whereby the shaft 28 may be rotated in either direction to turn the boltthreads into or out of the nut. The solid spindle 30 is enough shorterthan the shaft 28 that the pin 34 clears the rear end of the solidspindle. A motor or other power means may, of course, be employedinstead of the crank 32.

The forward end of the solid spindle 30 is provided with a chuck 36 forholding the heads of the bolts as they are driven into and out of thethreads of the nuts.

In order to neutralize the end thrust which would be occasioned if thebolt entering the nut were required to pull the traveling head I2 afterit, separate means is provided for moving the head I2 longitudinally ofthe bed at the exact rate required by the pitch of the threads beingtested. This means consists of a feed screw 38, which has an integraljournal portion 40 rotatably supported in the upright 24 and providedWith a driving gear 42 held onto the journal portion 40 by a set screw44. A collar 48 held on by set screw 48 prevents axial movement of thejournal portion 40. The gear 42 is driven by a pinion 43 through anidler pinion 45 rotatable on the stud 41. Pinion 43 is fast on thehollow shaft 28. The pinions 43 and 45 have a like number of teeth,which is half the number of 4 teeth on the gear 42, whereby the gear 42is driven at half the speed of the shaft 28.

As a consequence, the feed screw 38 is provided with threads havingdouble the pitch of the bolt being tested. For the larger sizes ofbolts, however, the feed screw 38 may have threads of the same pitch asthe bolt being tested, but in this case, a 1:1 ratio should existbetween hollow shaft 28 and the feed screw 38. This ratio may beprovided by removing the gear 42 and putting thepinion 45 in its place,then moving the idler stud 41 to the position 49 and placing the gear 42on the idler stud. Thus, for the larger sizes of bolts which the machinehas the capacity to test, the feed screw and the hollow shaft 28 willrotate at the same speed.

The torque measuring head I4, which occupies the middle portion of thebed plate |0 comprises a base 14 with two uprights 16 and 18 forcarrying the bearings 80, upon which the torque measuring spindle 82 isrotatable. The front end of the spindle 82 is squared, as at 84. Socket86 has one end fitted over the square part 84 and the other end 88 madeto fit the nut, which is being tested. Obviously, sockets 86 may be madewith openings 88 for various sized nuts, but all having the same opening84 for fitting over the spindle.

Fast on the back end of the spindle 82 is an indicator wheel 90, theteeth of which are formed as in a worm wheel. A transverse rod 92 has athreaded portion 94, the pitch of these threads corresponding to theteeth of the gear 90 with which they are in mesh. The rod 92 and gear 90do not, however, operate as a worm and Worm wheel, but instead, operatemore in the nature of a rack and gear movement, that is, when thetorque, which is applied by the head I2 to the socket 8S turns thespindle 84, the rotation of the gear 90 will operate the rod 92transversely of the machine. A grooved roller 81 carried upon a bracket89 which extends upward from the upright 16 is positioned above thethreaded portion 94 to just barely touch it, whereby the threaded end ofthe rod may not be inadvertently raised out of mesh with the indicatorwheel. The outer end of the rod rests on top of another grooved roller8| which is carried on a bracket 93 extending from the frame member 95.A hook member 99 is also carried on the bracket 93. Hook member 99prevents the rod 92 being inadvertently raised out of engagement withthe roller 8|. The mid-portion of the rod 92 is provided with an arm 96which carries a pencil 98, which is held by the weight 0f the arm on thepaper |00, which is, in turn, supported by a platen |0| carried on theframe members 95 and s1. The paper is supplied from a roll |02, thepaper passing over an idler roll |04 to a paper feeding roll |06. Theidler roll |04 and the feeding roll |06 are driven by worm and wheelgearing |0-| I2. The worm l0 is carried on a shaft |I4, which has a pinand slot connection ||6 ||8 with the tubular shaft |20. 'I'he tubularshaft |20 is driven by a rotor |22 shown in detail in Figs. 8 and 9, andin the assembly, Fig. 6. The rotor |22 is driven by gearing from thehollow shaft 28, but inasmuch as the shaft 28 is rotated by the crank 32alternately backward, then forward, means are provided for turning therotor in the same direction, irrespective of which direction the shaft2B rotates. This means comprises two gear trains connecting the shaft 28and rotor |22, the one gear train, which consists of a gear |24 on theshaft 28, meshing directly i ,i ,Whl shaft |20, whileftl 011th@ hollowShajf 130 through an idler pinion' 32. rotates freely` onv the stud[34.0*1 'ij'lfreI gear also free `on'the'tubular shaftflZU; n rangement,4no rnatterw 28 'is rotated, onev or th and |30 will'alwaysfbefra Thisis due to'the ratclirer and, pavvlc'ow tion Vwhich inlinevtelyjsuroundstlie rrofand comprisesndrumsfl3 an ,mth

ratchet teeth fljlThe teethiri b h, f identicalybothfbeing pawl willmoveithem so ,thatwhicheverjof"theJtwo gears" |26Jv o"r ['30 happens tobe rotating foryvardlyr will. ndriv the rotor |22 forwardly."

At the left endiofy thebe. l stock I6 isQsecur'edjbytheh nd'nu nut beineadaptedjit''daw.1ipat |54, which has agsiiide. portion its ii tudinallyinth'e slotfinth plate'` I0', whereby'jth t' and reset in any 'desiredThe tailstock consists ofjfa base right |60, which hasa caplg h ist."The unrightgl'et adjcap A I j vide rotative' bearing" for "the jspealljch u The chuck lljconsist'Sl Ofajbodyportion y brought to a smalleridiameter' tIfIQyvhret has rotative bearing' inthetail'htock averti;wheel `|`I2 being permanently sec r' tangular 'opening 1142" |16, whichmay bef The worm llillineslij u o a hand mit :az seins'.prjovliislfor Aworm. The .iaivsfl'lfslhavfe suit'ableinner e mations" at |34 togrip'ascuare torque The front end of thetorque rodA i'h iarged shank"laavwhicn 'ish' setscI ferent 'sizes for, testinb The islianks' `i g8,"however sothat the Same socket in' shaft 82 will hold a seriesw'oi rodsof different sizes.

`Calibratiori.- This machine m u togive atorefl'bf kQWnibCh-Dimd al igraph". Otherwise' it will g;-

not be possible to sure or d:eval/nate the test torqueresultsobtamed;"`V

f This is' accrnplishe'dumost readily by lever and dead .Weight torquerequired"o rthe l, Y assmbl the' .atprobriaiefosue fd i graph ofV'rnairirniirn"l'permips's'ibl'e' fr thaty torque (greaterl amplitudefisobtained: either by lengthening*,jfthefvrrod4 "or/byl ch smaller [rodf``1enve"tlie nut wrenc from the weigh Ishaft iit'f i ori- 7n venientlength, ik a" wi'rich;"ontg"t "bf the shaftg"4 suspend jafpoise Gori'known dead' weight tfrom;` heijoute u lever at" aineasureddistance"in/inches rni tie shaft center and at a point on thecenter line of of 'theA lev lever to .develop the desired torque in i lpoundsjlever `in inches lby weight in pounds);

turn man'gi'ilarV adjustment screw in tail stock unt Weighp-ifiifid*freeand centerline of heterisr isedjtp-levelposition;- operate crank totravel without regard-*fte centerline" of taper? ain oscillatethe'Qcranl tol 'move the A'paper to mark mitI q f amplitude produced bythe known appliedilever'v in inches 4by weight in s) ;me`asure4A thiswidth to thenearest hun' D diedth'oi an inch (0`.01);A divide theinchpounds of torque by this amplitude in inches `to get the calibrationratioor factor. (Not necessary to come out even, express lin decimals):repeat the operation if not satisfactory the rst ri time. When theamplitude of graph andthe ratio obtained rare satisfactoryadjust-pencilto center line of paper by turning adjusting screw in tail stock andclamp rmly to prevent any play; the machine is now calibrated ready fortiT'es'ting' ;When startirigeach test, write' the number, size and,thread data of the nut, together withfthecalibratien ratio'v(inch-pounds per inch) Gilfl ,flaifvelr to one 'side' 'of the grap toavoid'any possible mistake vof uncertainty later when measuring thegraph. 'f i W'hen the tests are finished, the test strip of graphs islaid out on a table' where the graph for each nut islmeasured at allspecified or de- 1 siren' "peints" iid the 'values'"tabuiatedfsiicnpintsusually include maximum and prevailing turques in firstinstallation and biothin'stallation and removal prevailing turques inthe iinal operation. The measurements are taken outward to either-sidefrom the center line in all cases and may be ltaken direct by steelscale or by means of dividersV and' scale; When all graphs have beenmeasured and tabulated, a slide rule is set to the calibration ratiowhich lis multiplied by the graph measurements to obtain inch-poundso'ftorque and tabulated in the next corresponding column for record.

Before starting the test, assemble the proper axial'feed screw; theninsert the bolt and screw l nut on with iingers vuntil self-'lockingdevice contacts the thread; slide bolt and nut assembly over to engagein wrench socket inr Weighing unit;starttest by turning crank to screwbolt into nuttof required number of turns -(usually i five 'or more);use'practical speedto obtain steadyl results-but not fast enough toheatv too hot for the fingers to hold, or as may be specified; .reverseandturn'back the seme number of turns'as used in installation even ifnut becomes loose'befoie' that number `is reached; repeat untilre'quirednumber of assembly operations have beeninade 'f' "1 lTlie'proper data'will be recorded automatically near' by each graphasdescribed above. Care mustlbe 'observed t avoid testing at a rate thatwillfcause irregularities such as over-shooting beyond. 'thetr'uetorque'. I

Torquel rods-High strength spring tempered torque rods with'highelasticlimitsh'ould be'used finordi" t'fgetl the greatest famount of angularelasticity out of the rod without injury and thus rd Jsufficiently to'mark starting lineove the' Weigltand then,4 by means' enable the use ofshorter lengths and smaller sizes.`

For steels heat treated to a tensile strength of 150,000 pounds persquare inch or above, it is safe to assume an elastic limit strength intorsion of 1A; of the tensile strength. Therefore, for the rods heattreated to a tensile strength of 200,000 lbs./sq./in./, it should besafe to apply a torsional stress of approximately 66,000 lbs./sq./in./without danger of causing permanent set. For rods of this quality, thisvalue may be substituted for S in the formula, S=TR/J for calculatingthe maximum allowable torque that may be applied to them.

For round rods, S=Tr/J becomes Substituting the above value,66,000=5.093 T/ d3, and T=66,000d3/5.093, or T=12.960d3, approx. Forother values of S the torque T would be found in the same manner.

T=torque in inch-pounds.

S=torsional stress, pounds per sq. in.

1'=radius of rod, ins.

d=diameter of rod, ins.

J :polar moment of inertia, =Td4/32 for round rods.

The maximum allowable torque that may be applied to square, hexagon, orother shapes of rods may be calculated in the same manner bysubstituting the proper values for J.

rllhe amplitude of graph produced by a given torque in a round rod maybe determined by the formula, m=32TLR/d4G, or m=.00000278TLR/d4, whereinT and d=as above Lzlength of rod, ins.

R=radius of indicator wheel (3 inc. in drawing) G=modulus of elasticityin torsion, lbs/sq. im:

11,500,000 for steel mzamplitude of graph, ins. (must be less than halfor paper width).

The length of rod required to give a desired amplitude of graph may becalculated by substituting that value for m, the rod diameter for d, andthe estimated torque for T in the above formula and then solving for L.

The amplitude of graph and the lengths of square rods or other shapesmay be calculated in like manner by substituting the correspondingvalues. A square rod will take a little more torque and give a littleless amplitude of graph than a round rod a diameter equal to the widthof the square rod.

By having a series of several sizes of high strength torque rods, itwill not be necessary to use very long rods. You must use rods bigenough to take the torque load developed by the nut and you must produceenough amplitude to make a graph wide enough to obtain measurements, ofsuiiicient accuracy to be dependable.

Keep the rod sizes down to a minimum for a maximum amplitude for actionand then add the necessary length to produce the desired amplitude. Withhigh strength rods this will keep the machine as short as possible. Anindicator wheel of larger diameter would give relatively greateramplitude of graph but would reduce sensitivity which would be veryundesirable in the smaller nuts where small diierences are important.

The ratio of paper travel to bolt turns may be changed by changing wormgear ratios to feed roller. A half inch of paper for five bolt turns hasbeen found practical but more would give betterdeiinition. Longitudinalrulings on the paper are desirable but not essential. The perioratedpaper with constant center line is a. great convenience because it staysadjusted to the same center.

As previously stated, it is not essential that the machine be calibratedeach time to an even number of inch-pounds per inch because a fractionalfactor can be used just about as readily and it Vwill save time whenCalibrating.

It would have been preferable to cause the drive shaft to feed in andout instead of moving the whole driving unit to and from the weighingunit to eliminate drag as the bolt was screwed in and out of the nut butno practical way was found to do it. Belts instead of gears have beenused to drive the recorder, but they have not been satisfactory becauseof too much slippage. Also, it would probably have been better to haveraised the axis of the machine higher above the bed to give more workingclearance. For best results, a light machine is best for nuts up toperhaps a half inch and a heavier one should be provided for the largernuts.

The operation of the device is as follows:

A nut, which is to be tested, is placed in the opening 88 of the socket86, and the corresponding bolt is held by the head in the chuck 35. Itmust now be determined what degree of torque, preferably in foot-pounds,will be required to turn the bolt into the nut if the nut issufficiently tight on the bolt. The hand wheel |82 on the upright |60may now be turned so as to bring the arm 96, which holds the pencil 98to a central position on the torque recorder` A suitable scale beam,preferably one cf one-foot length, may now be attached to the spindle82, preferably at the rear end thereof, in the neighborhood of the screw|90 and the predetermined weight necessary for turning the bolt threadinto a nut of the proper tightness Iapplied to the outer end of thescale beam. If this predetermined weight moves the pencil 98 laterallyon the recorder a satisfactory distance, then it may be assumed that atorque rod of the proper tension has been selected. The weight and scalebeam may now be removed.

With the hand crank 32, the bolt threads are now turned into those ofthe nut. The nut will, of course, resist being turned onto the boltthreads, and will therefore twist the spindle 82 and the gear 90 againstthe resistance of the torque rod |86. If the pencil 98 has moved as farlaterally as it was previously moved by the scale beam and weight, thethreads are of the proper tightness.

The hand crank 32 is now turned in the reverse direction so as to screwthe bolt threads out of those of the nut, whereupon the twist on thetorque rod |86 is opposite to that rst recorded, and the pencil 98 willconsequently move laterally but in the opposite direction, this process,that is, reversal in direction of the hand crank 32, may be repeatedfour or iive times, each reversal being indicated by movement of thepencil away from its central position.

The paper |00, will, of course, during all of this procedure, be movingdownward toward the feeding roll |06, whereby the oscillations of thepencil will produce a graph substantially as indicated in Fig. 11, eachoscillation being somewhat shorter than the one previous because of agradual slight loosening of the nut threads is provided rn 'tn (Fortesting at specialtempe atures Ai on the bolt threads as reverserotations are drepeated.

degree of heat to the Vbolifaridr'iut while the test l is being made.For sub-normaltemperatures,

a 'rfrig'erating unit i''th'sanifsizemay' be' set at a desiredtemperature and *simil'erly"applie'd;vlv

Whentestiuaat elevatedteluperatufe Special extension wrench sockets4areprovided to extend insidethe furnace fromth l"ends and hold boit andnut for testing-)1A thermocoup tendsin through the socktr m weiglii ,Ato contact` the nut forindicating temperature.

Ihe temperatureis then measured by means of lpotjentiometer at convegnit locat n;

'chuck does `notextendr into the rnace.

v is necessaryto provide'` extension sockets, or holdem, in lieu'of'socket'and' chuck 36 to holdtlieA nut and threaded end of bolt midwayin the fur--` nace where the test is made as at normal temperature. Insuch case the extension socket for 3B should be tubular to carry athermocouple in to contact the nut to indicate temperature during thetest. The thermocouple leads out to a standard potentiometer by means ofwhich the temperature is measured as in other tests.

Having described my invention, I claim:`

l. In an apparatus for testing the tightness of externally threadedparts in internally threaded parts, the combination of a base; a torqueapplying unit on said base having means for holding one of said parts,and means for rotating said holding means in either direction; a torqueweighing unit on said base having means for receiving the other of saidparts, means for resiliently restraining said receiving means fromrotating, and means for securing one end of said restraining means forunitary rotation with said receiving means; a torque resisting unit onsaid base having means for gripping the other end of said resilientrestraining means, means for rotatably adjusting the said other end ofthe gripping means and means for longitudinally adjusting the saidgripping means; a torque recording unit on said base having means formoving a graph paper with respect to said base, a pencil or the likeadapted for contacting said paper, and a movable support for saidpencil; means associated with said torque weighing unit and said torquerecording unit operative upon rotative movement of the receiving meansof said torque weighing unit in one or the other directions to causemovement of said pencil transverse to the movement of said paperin oneor the other direction; means associated with said torque recording unitand said torque applying unit operative by rotation of said holdingmeans of Isaid torque applying unit in either direction to move saidpaper longitudinally in the same direction; and means associated withsaid torque applying unit and said torque weighing unit operative uponrotation of the holding means of said torque applying unit in one or theother direction to cause relative longitudinal movement between saidtorque applying unit and said torque weighing unit in one or the otherdirection in correspondence with the lead of the parts being tested.

fthe

' The thetorque ap lying kunit comprises a spindle le r'ta'tabl 'fm nsn-on4k aid-spindle;

g matiteI bearing 11i-said3 need,

e, akfgear train l.on said headonnecting' ids Veine apparatusdennednai-i111 wherein ait @reprises as mille aid 5. The apparatus dened inclaim 1 wherein the torque recording unit comprises a paper supply roll,an idler roll and a feed roll, a frame for rotatably supporting saidrolls, a platen for supporting the paper, rotation transmitting meansextending from said torque applying unit for rotating said feed roll tomove said paper always in the same direction, and motion transmittingmeans extending from the torque weighing unit for moving said pencilcrosswise of the movement of said paper.

6. In an apparatus for testing the tightness of externally threadedparts in internally threaded parts, the combination of a base; a torqueapplying unit on said base adapted for holding and rotating one of saidparts; a torque weighing unit on said base adapted for receiving theother of said parts; means for resiliently restraining said receivingmeans from rotating; a torque recording unit associated with said torqueweighing unit adapted for supporting and moving a graph paper in onedirection only and with a pencil or the like adapted for contacting saidpaper and moving in one or the other direction crosswise of the movementof said paper by rotation of the receiving means of the torque weighingunit in one of the other direction; cooperating means between saidtorque applying unit and said torque recording unit adapted for movingsaid graph paper always in the same direction upon rotation of theholding means of the torque applying unit in either direction; and meansadapted upon rotation of the holding means of the torque applying unitto cause relative longitudinal movement between said torque applyingunit and said torque weighing unit corresponding to the lead of thethreads on the parts being tested.

7. In an apparatus for weighing the torque required to rotate one of twofriction coupled parts with respect to the other, the combination of asupporting frame; torque applying means on said frame for holding androtating one of said parts, torque Weighing means on said frame forreceiving the other one of said parts and yieldingly restraining it fromfree rotation, a graph paper, a pencil, means operative by rotation ofsaid torque applying means in either direction to ll' move said graphpaper in one direction only, and means operative by yielding rotation ofsaid Weighing means in either direction to draw said pencil over saidgraph paper in either direction crosswise of the direction of themovement of said paper.

8, Apparatus for continuously recording the torque required to cause afeeding movement in either direction between two interengaging threadedelements by relative rotation of the threaded elements, comprising meansfor restraining one of said threaded elements against rotation, meansfor applying torques to the other of said threaded elements rst in onedirection, then in the other to cause opposite relative rotationsbetween said threaded elements, a torsion dynamorneter associated withone of said elements for measuring the value of the applied torques,said torsion dynamometer including a dynamometer element movable from aneutral position in either direction in accordance with the directionand magnitude of the applied torques, a recording mechanism associatedwith said dynarnometer element which comprises-a graph strip and awriting point resting on said strip, means actuated by movement of saiddy nainometer element in one or the other direction t inove said writingpoint in` one or the other direction transversely of said strip, andmeans operative by movement of said torque applying means in eitherdirection to move said strip lengthwise in the same direction.

DAVID M. WARNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

